Remove static dependency on bcrypt.dll, advapi32.dll, userenv.dll

- Make `home_dir_crt` return `None` if the required WinAPI functions are not available
- Fall back to `RtlGenRandom` if `BCryptGenRandom` is not supported
- Fall back to custom `hashmap_random_keys` implementation if `RtlGenRandom` is also not supported

Author: seritools

library/std/src/sys/windows/c.rs

@@ -535,6 +535,69 @@ compat_fn_with_fallback! {
     }
 }
 
+compat_fn_with_fallback! {
+    pub static ADVAPI32: &CStr = ansi_str!("advapi32");
+    const LOAD: bool = true;
+
+    // >= NT 3.1+
+    // https://docs.microsoft.com/en-us/windows/win32/api/processthreadsapi/nf-processthreadsapi-openprocesstoken
+    pub fn OpenProcessToken(
+        ProcessHandle: HANDLE,
+        DesiredAccess: DWORD,
+        TokenHandle: *mut HANDLE
+    ) -> BOOL {
+        rtabort!("unavailable")
+    }
+
+    // RtlGenRandom
+    //
+    // >= Vista / Server 2008
+    // https://docs.microsoft.com/en-us/windows/win32/api/ntsecapi/nf-ntsecapi-rtlgenrandom
+    pub fn SystemFunction036(RandomBuffer: *mut u8, RandomBufferLength: ULONG) -> BOOLEAN {
+        rtabort!("unavailable")
+    }
+}
+
+compat_fn_with_fallback! {
+    pub static BCRYPT: &CStr = ansi_str!("bcrypt");
+    const LOAD: bool = true;
+
+    // >= Vista / Server 2008
+    // https://docs.microsoft.com/en-us/windows/win32/api/bcrypt/nf-bcrypt-bcryptgenrandom
+    pub fn BCryptGenRandom(
+        hAlgorithm: LPVOID,
+        pBuffer: *mut u8,
+        cbBuffer: ULONG,
+        dwFlags: ULONG
+    ) -> NTSTATUS {
+        if RtlGenRandom(pBuffer, cbBuffer) == TRUE as _ {
+            0 // STATUS_SUCCESS
+        } else {
+            0xC0000001u32 as i32 // STATUS_UNSUCCESSFUL
+        }
+    }
+}
+
+#[inline(always)]
+pub unsafe fn RtlGenRandom(RandomBuffer: *mut u8, RandomBufferLength: ULONG) -> BOOLEAN {
+    SystemFunction036(RandomBuffer, RandomBufferLength)
+}
+
+compat_fn_with_fallback! {
+    pub static USERENV: &CStr = ansi_str!("userenv");
+    const LOAD: bool = true;
+
+    // >= NT 4
+    // https://docs.microsoft.com/en-us/windows/win32/api/userenv/nf-userenv-getuserprofiledirectoryw
+    pub fn GetUserProfileDirectoryW(
+        hToken: HANDLE,
+        lpProfileDir: LPWSTR,
+        lpcchSize: *mut DWORD
+    ) -> BOOL {
+        rtabort!("unavailable")
+    }
+}
+
 #[link(name = "kernel32")]
 extern "system" {
     pub fn LoadLibraryA(lpFileName: LPCSTR) -> HMODULE;
@@ -567,4 +630,7 @@ extern "system" {
         lpDistanceToMoveHigh: *mut LONG,
         dwMoveMethod: DWORD,
     ) -> DWORD;
+
+    pub fn GetTickCount() -> DWORD;
+    pub fn GetCurrentThreadId() -> DWORD;
 }

library/std/src/sys/windows/c/windows_sys.lst

@@ -2176,10 +2176,8 @@ Windows.Win32.Networking.WinSock.WSASYSNOTREADY
 Windows.Win32.Networking.WinSock.WSATRY_AGAIN
 Windows.Win32.Networking.WinSock.WSATYPE_NOT_FOUND
 Windows.Win32.Networking.WinSock.WSAVERNOTSUPPORTED
-Windows.Win32.Security.Authentication.Identity.RtlGenRandom
 Windows.Win32.Security.Cryptography.BCRYPT_ALG_HANDLE
 Windows.Win32.Security.Cryptography.BCRYPT_USE_SYSTEM_PREFERRED_RNG
-Windows.Win32.Security.Cryptography.BCryptGenRandom
 Windows.Win32.Security.Cryptography.BCRYPTGENRANDOM_FLAGS
 Windows.Win32.Security.SECURITY_ATTRIBUTES
 Windows.Win32.Security.TOKEN_ACCESS_MASK
@@ -2523,7 +2521,6 @@ Windows.Win32.System.Threading.InitOnceBeginInitialize
 Windows.Win32.System.Threading.InitOnceComplete
 Windows.Win32.System.Threading.LPTHREAD_START_ROUTINE
 Windows.Win32.System.Threading.NORMAL_PRIORITY_CLASS
-Windows.Win32.System.Threading.OpenProcessToken
 Windows.Win32.System.Threading.PCONDITION_VARIABLE
 Windows.Win32.System.Threading.PROCESS_CREATION_FLAGS
 Windows.Win32.System.Threading.PROCESS_INFORMATION
@@ -2571,6 +2568,5 @@ Windows.Win32.System.Threading.WaitForSingleObject
 Windows.Win32.System.WindowsProgramming.IO_STATUS_BLOCK
 Windows.Win32.System.WindowsProgramming.OBJECT_ATTRIBUTES
 Windows.Win32.System.WindowsProgramming.PROGRESS_CONTINUE
-Windows.Win32.UI.Shell.GetUserProfileDirectoryW
 // tidy-alphabetical-end
 

library/std/src/sys/windows/c/windows_sys.rs

@@ -7,29 +7,6 @@
 // Bindings generated by `windows-bindgen` 0.49.0
 
 #![allow(non_snake_case, non_upper_case_globals, non_camel_case_types, dead_code, clippy::all)]
-#[link(name = "advapi32")]
-extern "system" {
-    pub fn OpenProcessToken(
-        processhandle: HANDLE,
-        desiredaccess: TOKEN_ACCESS_MASK,
-        tokenhandle: *mut HANDLE,
-    ) -> BOOL;
-}
-#[link(name = "advapi32")]
-extern "system" {
-    #[link_name = "SystemFunction036"]
-    pub fn RtlGenRandom(randombuffer: *mut ::core::ffi::c_void, randombufferlength: u32)
-    -> BOOLEAN;
-}
-#[link(name = "bcrypt")]
-extern "system" {
-    pub fn BCryptGenRandom(
-        halgorithm: BCRYPT_ALG_HANDLE,
-        pbbuffer: *mut u8,
-        cbbuffer: u32,
-        dwflags: BCRYPTGENRANDOM_FLAGS,
-    ) -> NTSTATUS;
-}
 #[link(name = "kernel32")]
 extern "system" {
     pub fn CancelIo(hfile: HANDLE) -> BOOL;
@@ -560,14 +537,6 @@ extern "system" {
 extern "system" {
     pub fn RtlNtStatusToDosError(status: NTSTATUS) -> u32;
 }
-#[link(name = "userenv")]
-extern "system" {
-    pub fn GetUserProfileDirectoryW(
-        htoken: HANDLE,
-        lpprofiledir: PWSTR,
-        lpcchsize: *mut u32,
-    ) -> BOOL;
-}
 #[link(name = "ws2_32")]
 extern "system" {
     pub fn WSACleanup() -> i32;

library/std/src/sys/windows/os.rs

@@ -280,6 +280,10 @@ pub fn temp_dir() -> PathBuf {
 
 #[cfg(not(target_vendor = "uwp"))]
 fn home_dir_crt() -> Option<PathBuf> {
+    if !c::GetUserProfileDirectoryW::available() || !c::OpenProcessToken::available() {
+        return None;
+    }
+
     unsafe {
         // The magic constant -4 can be used as the token passed to GetUserProfileDirectoryW below
         // instead of us having to go through these multiple steps to get a token. However this is

library/std/src/sys/windows/rand.rs

@@ -1,20 +1,27 @@
 use crate::ffi::c_void;
 use crate::io;
+use crate::mem::MaybeUninit;
 use crate::mem;
 use crate::ptr;
 use crate::sys::c;
 
 pub fn hashmap_random_keys() -> (u64, u64) {
-    let mut v = (0, 0);
-    let ret = unsafe {
-        c::BCryptGenRandom(
-            ptr::null_mut(),
-            &mut v as *mut _ as *mut u8,
-            mem::size_of_val(&v) as c::ULONG,
-            c::BCRYPT_USE_SYSTEM_PREFERRED_RNG,
-        )
-    };
-    if c::nt_success(ret) { v } else { fallback_rng() }
+    if c::BCryptGenRandom::available() {
+        let mut v = (0, 0);
+        let ret = unsafe {
+            c::BCryptGenRandom(
+                ptr::null_mut(),
+                &mut v as *mut _ as *mut u8,
+                mem::size_of_val(&v) as c::ULONG,
+                c::BCRYPT_USE_SYSTEM_PREFERRED_RNG,
+            )
+        };
+        if c::nt_success(ret) {
+            return v;
+        }
+    }
+
+    fallback_rng()
 }
 
 /// Generate random numbers using the fallback RNG function (RtlGenRandom)
@@ -25,12 +32,25 @@ pub fn hashmap_random_keys() -> (u64, u64) {
 #[cfg(not(target_vendor = "uwp"))]
 #[inline(never)]
 fn fallback_rng() -> (u64, u64) {
-    let mut v = (0, 0);
-    let ret = unsafe {
-        c::RtlGenRandom(&mut v as *mut _ as *mut c_void, mem::size_of_val(&v) as c::ULONG)
-    };
+    if c::SystemFunction036::available() {
+        let mut v = (0, 0);
+        let ret = unsafe {
+            c::RtlGenRandom(&mut v as *mut _ as *mut c_void, mem::size_of_val(&v) as c::ULONG)
+        };
+        if ret != 0 { v } else { panic!("fallback RNG broken: {}", io::Error::last_os_error()) }
+    }
 
-    if ret != 0 { v } else { panic!("fallback RNG broken: {}", io::Error::last_os_error()) }
+    unsafe {
+        let tick_count = c::GetTickCount();
+        let id = c::GetCurrentThreadId();
+        let mut file_time: c::FILETIME = MaybeUninit::zeroed().assume_init();
+        c::GetSystemTimeAsFileTime(&mut file_time as *mut _);
+
+        (
+            (file_time.dwHighDateTime as u64) << 32 | tick_count as u64,
+            (id as u64) << 32 | file_time.dwLowDateTime as u64,
+        )
+    }
 }
 
 /// We can't use RtlGenRandom with UWP, so there is no fallback